Borislav Sarafov, the deputy chief prosecutor, said on Sunday that Enimehmedov faces up to five years in prison on the grave hooliganism charge and up to six years on the death threat charge.

Police identified the attacker as 25-year-old Oktay Enimehmedov - an ethnic Turk from the eastern city of Burgas - who targeted Ahmed Dogan while he was speaking at a conference of his liberal Movement for Rights and Freedoms (MRF).

MRF has accused the police and security services of failing to protect Dogan and demanded that the police investigate who was the "political mastermind" behind the attack.

In the footage, Dogan can be seen swiping away his attacker's outstretched arm before any shot is fired. The weapon appeared to have jammed.

Several men in suits then wrestled the attacker to the ground before he was subjected to a drawn-out beating, in which he was repeatedly kicked and punched.

Police experts examined the small handgun and said it would not have threatened Dogan's life, even if fired from close quarters. The three bullets loaded in it could have only caused minor skin burns, they added.

Third political power

Nedelcho Stoychev, the police psychology institute chief, said on Sunday that the attacker did not really intend to kill Dogan but only to frighten him, to show him that he "was not untouchable" while getting "his five minutes of fame".

Enimehmedov feared he himself might die in the incident and left a letter that police found in his Sofia flat, Stoychev said.

Prosecutors are also considering whether to press charges against some of those captured on video kicking the prostrate assailant after he was disarmed, prosecutor Sarafov said.

Dogan, who played a key role in Bulgaria's post-communist transition and won crucial rights for the country's near 10-percent minority of ethnic Turks, announced his planned resignation hours after the attack that put his party back in the spotlight.

The experienced and the versatile politician, who had led the MRF since its formation 23 years ago, named his deputy Lyutvi Mestan as successor. He however agreed to remain an honorary MRF chairman for life.

Under his leadership, the liberal MRF party was traditionally the third political power in the country and participated in two successive coalition governments between 2001 and 2009.

It is now in opposition to the right-wing government of Prime Minister Boyko Borisov.

The attack against the controversial politician was condemned by all political parties.